The present invention relates to a fluid flow control system, assembly and method and, more particularly, to a system, assembly and method utilizing reeled tubing for controlling the flow of fluid in oil and gas earth wells.
In the operation of subterranean oil and gas earth wells, it is often necessary to control the flow of fluid through the production tubing and into the annulus between the tubing and the wellbore casing. For example, in stimulation techniques the wellbore casing passes through a formation in the earth well and a pressurized fluid is passed through the production tubing and then laterally through appropriate openings formed in the tubing into the annulus between the tubing and the wellbore casing. Perforations are provided in the latter casing for directing the fluid into the formation for stimulating the recovery of oil and gas.
Known techniques of this nature employ threaded tubing for selective conveying of the fluid from the ground surface to the perforated casing. Although reeled tubing has been used in connection with production tubing to perform other functions there has been no known effective use of reeled tubing for conveying stimulation fluid into the annulus between the production tubing and the casing probably due to the need for relatively sophisticated high pressure sealing and blow-out prevention techniques. There is a need for reeled tubing in these types of operations since the reeled tubing has several advantages. For example, it can be more rapidly inserted into the well and can be more easily passed through downhole equipment. Also, the reeled tubing can traverse highly deviated, or horizontal, wells which could otherwise not be traversed with wireline or threaded tubing in a controlled manner.